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Seam tracking system for Weld
Automation
Welding Research Institute (WRI) has developed seam-tracking systems which can be
effectively employed for welding automation. Two different types of weld seam trackers
have been developed at WRI. The first type of seam tracker is based on non-contact
inductive type position sensor and the second type is based on through-the arc sensing.
Ministry of Information Technology (MIT) has sponsored this development.
The inductive sensor based seam tracker can be applied for fillet welds in large beams,
circular fillets of flanges etc. Through the arc sensing based seam tracker can be
employed with oscillating torch GMAW as the process for butt welded joints The major
benefits of employing seam trackers are Improved quality and increased productivity of
welded joints by avoiding defects due to mis-alignment of seams. Precise control over the
job conditions during welding and less dependency on the operator are additional
benefits.
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Versatile All Position In-situ metallographic polishing Equipment (VAPINE)
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Over the years a number of special
purpose in-situ polishing devices such as Controlled Electro Polisher In-situ (CEPIN), All
Position In-situ Electro polisher (APINE) and Versatile All position In-situ Electro
polisher (VAPINE) have been developed to enable metallographic polishing in difficult
location. With these techniques it is also possible to carry out high quality replication
even on warm components. |
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Narrow Gap Submerged Arc
Welding Technology |
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Conventional arc welding techniques
make use of wider weld grooves with included angles of 60-90º for plate thickness upto 50
mm in general. For higher thickness, the edge preparation comprises of a relatively wider
root preparation with 10 to 20º included angle. The edge preparations call for
considerable deposition of weld metal and consumption of flux. Modern fabrication
techniques aim at maximising productivity and cost savings. Narrow Gap Welding Technique
applied to conventional arc welding processes is a potential tool for welding fabrication
industry for achieving this goal especially for welding of thick section joints using
submerged arc welding. WRI has developed modular type narrow gap welding head, which can
be interfaced with conventional Submerged Arc Welding system having suitable rigidity.
Narrow Gap technology has been established for butt welding steel plates upto 180 mm
thickness. |
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Applications of high energy density
Electron Beam Welding Technology |
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Electron Beam Welding (EBW) facility
available at WRI was retrofitted with CNC controlled positioning tables and control
systems. With this facility, welding of stainless steel, aluminium and copper alloys have
been successfully established and applied to industrial products. |
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Jobbing & Repair
services |
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WRI has carried out number of repair jobs for critical
applications involving various types of cast iron, alloy steels and non-ferrous alloys.
These include
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Severely damaged hydro turbine runners weighing 13 tonnes made of
martensitic stainless steel. |
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Extensively cracked Nickel valve casting of chemical plants. |
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Circumferentially cracked Carbon Manganese hydraulic steel cylinders of
paper mill. |
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As a part of the continuing
community service, temple bells of Brahadeeswar temple, Thanjavur and Swaminathaswamy
temple, Swamimalai were repaired and handed over to the
temple authorities. |
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Worn out forged dies, steel roll mills, bowl mill coal crusher rolls and
crane wheels. |
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Severely cracked ancient church and temple bells made of bronze. |
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Fabrication of components for Aluminium bridges, foundation bolts, damper
flappers, MgO filled thin sheet thermocouples |
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Surfacing of pulverising rolls, valve wedges, seat rings |
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Development of Electrodes &
Fluxes |
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Following stick electrodes and Submerged Arc Welding
fluxes have been developed. |
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General purpose all position
welding electrodes conforming to AWS E 6012, E 6013, E 7018. |
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Low Alloy Steel Electrode conforming to E7018A1, E8018 B2 & E9018 B3. |
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Austenitic stainless steel electrode conforming to AWS E308 with controlled
ferrite, E410 & E430. |
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Special purpose hardfacing electrode for sugar cane crusher rolls and worn
out components of cement industry. |
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Fused flux for high speed and Narrow Gap welding techniques. |
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Development of Welding
Procedure |
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Extensive weldability evaluation of
indigenously developed high strength low alloy steel and quenched & tempered steels
for structural and pressure vessel applications have been done. The susceptibility of the
materials for hot cracking, hydrogen induced cold cracking and lamellar tearing was
thoroughly examined using different types of weldability tests. Welding parameters have
been optimized and safe welding procedures have been recommended. Welding procedures have
also been established for a variety of industrial components such as heat exchangers,
pressure vessels, pen stocks, steam turbines and number of critical applications to enable
arriving at appropriate Welding Procedure Specifications. |
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Remaining Life
Assessment of Power and Process plants |
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Remaining
Life and Condition Assessment studies of several Power, Chemical, Process and Fertilizer
plants have been conducted through elaborate Non Destructive Examination and In-situ
metallography
The extent, nature and type of damage have been thoroughly analysed and recommendations on
appropriate Run-Retire-Repair and periodicity of inspection have been made. |
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Major Projects Completed
